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Old 01-17-2015, 02:03 PM   #1
ioncannon
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Default ABS Light on, Radio cutting out... alternator?

So a few days ago I was driving home when I heard a weird whine that got louder as the engine reved up. I traced it down to my Accessport. Unplugging it made it go away. As I drove around, I noticed the headlights would flicker, especially when I hit the brakes. I parked the car and watched it, and the lights just began to flicker more and the ABS light went on. I reset the car and it stopped doing that.

I didn't see any issue for a couple more days.

Well today it seems that got worse. Every time I pushed the brakes to slow down while moving, the ABS light would light up and the radio would cut out. I could feel the ABS engage if I pressed harder. This would last 3-5 seconds and then the light would turn off and radio would come back on.

At one point the whole instrument cluster turned off and then turned back on.

On the way back home I turned off the radio and didn't see any of these problems.

The battery was changed a few months ago and from what my Accessport was reading, it had a 12-13v charge. Is it the alternator dieing? It may explain the whine from the AP?
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Old 01-17-2015, 02:57 PM   #2
Cougar4
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From what you stated about the trouble it does seem that the alternator is a prime suspect. You should have it load tested. Also check the connections to it and clean the battery connections even if they look okay.
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Old 01-17-2015, 05:40 PM   #3
Mulder
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Is that 12-13V with the engine running? If so there is definitely a charging problem.
Please add your car and location information to your profile so we can assist you more accurately.
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Old 01-17-2015, 10:43 PM   #4
ioncannon
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Quote:
Originally Posted by Mulder View Post
Is that 12-13V with the engine running? If so there is definitely a charging problem.
Please add your car and location information to your profile so we can assist you more accurately.
Yes, while it was idling. I have updated the info.
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Old 01-18-2015, 03:49 PM   #5
Cougar4
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Flickering lights and whine are symptoms of excessive AC voltage ripple coming from the alternator due to bad diodes inside it. You can disable the alternator by removing the rear connector going to it. Then start the engine and see if the troubles go away. The battery warning light will be on of course but if the alternator was causing the trouble then things should be working okay when it is disabled. This is an easy way to identify where the trouble is coming from.
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Old 01-20-2015, 07:12 PM   #6
ioncannon
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Quote:
Originally Posted by Cougar4 View Post
Flickering lights and whine are symptoms of excessive AC voltage ripple coming from the alternator due to bad diodes inside it. You can disable the alternator by removing the rear connector going to it. Then start the engine and see if the troubles go away. The battery warning light will be on of course but if the alternator was causing the trouble then things should be working okay when it is disabled. This is an easy way to identify where the trouble is coming from.
So I saw it happen again today, and today was -9c. Well after parking my car I turned on all lights and accessories. I saw everything start to flicker. Well, I turned on the power window motors and the same symptoms appeared (lights turning off, abs light, etc). Turning on all 4 actually cause all lights and accessories to sputter out. Engine still ran though.

So I guess this confirms it's the alternator. Question though, why would the engine run ok while the accessories all die out? Why does this mostly happen in the cold? I guess it's these diodes you wrote about?
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Old 01-20-2015, 07:22 PM   #7
Cougar4
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Check for loose connections between the alternator and the battery, the battery and fuse panel under the hood, along with cleaning the battery connections and chassis ground.

The trouble could also be within the ignition switch ACC portion of it. Also check the Main Fuse in the panel under the hood to make sure the nuts are tight that hold it in place.

Last edited by Cougar4; 01-21-2015 at 01:22 PM.
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